What To Do (& Not Do) When Your Car Overheats?

Who wouldn’t be frustrated and scared to see smoke coming from under the hood as they’re out on a summer drive? Overheating engines can and do happen, and the damage can be permanent if the right precautions and actions aren’t taken. Engines that run too hot can cause damage and ruin your journey.

An overheating engine is a sign of a problem with your vehicle’s coolant system. If your car overheats quickly, you should see a mechanic. If your car is running hot but not overheating, it’s a warning sign that there’s a problem, and you should have it inspected.

Why Do Engines Overheat? A List of Possible Causes

Engines can overheat for many reasons. In general, it’s because something’s wrong within the cooling system and heat isn’t able to escape the engine compartment. The source of the issue could include a cooling system leak, bad radiator fan, faulty water pump, low engine oil level, or thermostat failure.

Regardless of the problem’s source, an overheating engine isn’t something you want to let linger. Your engine could sustain serious, if not permanent, damage.

Why Do Engines Overheat

#1. Cooling System Leak.

A car’s cooling system is in charge of regulating heat coming from the engine. It does this by circulating coolant through the hot zones around the engine block and cylinder heads and then back to the radiator.

When coolant leaks from the system, the temperature of your engine will climb and, eventually, overheat. A coolant leak can come from a faulty hose, worn-out gasket, cracked engine block, and even damage to the radiator.

Keeping up with regular inspections and maintenance is the best way to avoid coolant leak issues and damage from an overheated engine.

#2. Faulty Water Pump.

Coolant doesn’t circulate all on its own. Your engine’s water punch is typically considered to be the most important part of your car’s cooling system because it controls the flow of coolant through the whole system.

When your water pump is unstable, there’s internal erosion, or if the system becomes contaminated, the pump may stop working correctly. If your engine overheats, always check the water pump first because without a proper pump function, there’s no hope of getting your engine working again.

#3. Bad Radiator.

When it comes to your vehicle’s cooling system, think of the radiator as the command center. A coolant and water mixture are constantly circulated from the radiator to the engine to absorb excess heat. Then, when the coolant returns to the radiator, it uses a series of fins to cool down and extract heat out of the coolant/water mixture.

How can a radiator go bad? Blocked passages can cut off the flow of coolant, so heat can’t transfer away from the engine.

Damaged or bent radiator fins can make it more difficult for the radiator to extract heat from the returning coolant. And finally, a leak in the radiator can drain the system of coolant, which is the lifeblood of your vehicle’s cooling system.

#4. Low Engine Oil Level.

Car engines use a lot of moving parts to ignite fuel that gets your vehicle on the move. Engine oil provides essential lubrication to each engine component to reduce heat-generating friction. When engine oil levels are too low, poorly lubricated parts will create more friction and buildup heat.

In addition, the engine oil also helps transfer heat away from the engine – just like coolant. Heat stress and even serious engine damage can result from low engine oil levels.

Staying on top of regular engine oil changes is the best way to avoid this problem altogether. Take indicators seriously, like your dashboard oil light, and get your car to a technician as soon as possible if you think your engine oil levels are too low. Better safe than sorry!

#5. Thermostat Failure.

One of the most common reasons that your engine may overheat is due to a malfunctioning thermostat – but the thermostat inside your car is rather different from the one in your house. In your home, your thermostat keeps track of the temperature and triggers the heat or air conditioning system to turn on, depending on its settings.

But if your house gets too hot and nothing happens, you’ll notice and open some windows, turn on fans, or take other steps to fix the problem, even if you have to wait for a repairman.

When your engine gets too hot, however, you can’t do anything to remedy the problem. That’s because your engine thermostat is actually a valve that controls the flow of coolant. When the engine gets hot, the valve opens and coolant flows through to reduce the engine temperature, while a cool engine has a closed valve that blocks the flow of coolant and helps a cold engine warm up.

A broken thermostat might be stuck in the closed position, causing the engine to warm up – and then keep going. No matter how hot the engine gets, the coolant is unable to pass through. This is a real problem and can cause your engine to overheat rapidly.

Signs Your Engine Is Overheating

If you’re able to take steps to cool your engine before it overheats to the point of failing, you may reduce the risk of irreversible engine damage. But first, you’ve got to notice the symptoms of overheating, which can include:

#1. Temperature Gauge.

Most cars contain a temperature gauge on the dashboard. While you might be tempted to think this reflects the outdoor temperature (some cars have this feature, too) the temperature gauge reflects how hot your engine is. When you see it rising towards the red temperature indicator, your engine is overheating. Once it reaches the red indicator, your engine has become dangerously hot.

#2. Overheating Dashboard Light.

You may also see a dashboard light telling you that your car is experiencing trouble. If you notice a thermometer dashboard light sitting above a wavy line, this is your radiator fluid light (also known as a coolant warning). The radiator warning lights up when your engine begins overheating.

#3. Clicking or Clanking Car Noises.

Engine oil is responsible for keeping your engine working together. In an overheating engine, your oil will begin to lose its lubrication properties. In these cases, you might begin to hear your engine components clicking or clanking as they work together without the buffer of your oil.

#4. Steam, Smoke, or Vapor.

Radiator fluid is a mixture of antifreeze, water, and corrosion inhibitors. The boiling point of radiator fluid is often between 223°F and 235°F (depending on the mixture ratios). Meanwhile, the average temperature of a normally operating car engine is between 195°F and 220°F.

As your engine starts overheating, its temperature will exceed the boiling point of your radiator fluid. When your radiator fluid boils, it may escape from under your hood in the form of steam, vapor, or white smoke.

#5. Unusual Engine Smells.

In the case of an overheated engine, some drivers say they can smell the heat. Here is a look at three smells that may indicate an overheating engine:

  • Burning plastic smell: From plastic valves to rubber seals, vulnerable engine components may begin to melt as your engine overheats, emitting the smell of burning plastic.
  • Sickly sweet car smell: The coolant in radiator fluid is ethylene glycol, which is molecularly similar to the sugar compound. As such, it can smell sweet when it burns. Some drivers describe it as smelling like maple syrup or butterscotch.
  • Burning oil smell: As your engine oil begins to burn, it is said to carry a sulfur-like smell. Other drivers describe this smell as similar to burning fuel.

#6. Performance Troubles.

When your engine is overheating, your vehicle may face acceleration and performance struggles. Why? If you think back to your high school days, you might remember that cold air is denser than warm air.

The density of the cool air intake helps sustain your engine’s combustion process—which fuels your vehicle’s momentum. As such, the excess heat can throw off your air/fuel mixture, creating performance issues.

The Dos and Don’ts of What To Do When Your Car Overheats

Uh-oh! It’s happened! Now what? Here’s your step-by-step game plan of what to do:

  • DO Immediately turn off the air conditioner. This will help reduce stress on the engine and cooling system.
  • DO turn up the heat. Huh? Crank the heat? Yes! This will help divert heat away from the engine.
  • DO find a safe place to pull over and shut off the engine.
  • DO allow the engine to cool for at least 15 minutes. Keep an eye on the gauge (if equipped), waiting until it moves back to the normal range.
  • DO take out your phone. You need to get your car to a repair shop, so call a friend or a tow truck.
  • DO add radiator fluid (if you have it). A quick top-off could help protect your engine from further damage.
  • DO carefully restart the engine (if your car isn’t being towed). Drive to the nearest repair shop, all the while keeping an eye on the gauge/light. If it begins to creep up/illuminate again, pull over and let it cool.

Knowing what to do when your car overheats is important. So is knowing what not to do:

  • DON’T just continue on to your destination. Your overheated engine may still be running, but it’s not fine. You risk costly damage to your engine if you keep driving.
  • DON’T panic. Your engine may have lost its cool, but now is the time for you to keep yours! Drive carefully until you find a safe place to pull over.
  • DON’T open the hood immediately. It’s hot in there, and you risk being burned if you act too soon. Wait until the gauge moves back to the normal range or the light extinguishes before you open the hood.
  • DON’T wait for it to get better on its own. An overheating engine won’t repair itself, and you should bring your car in to mechanic as soon as you can.

Tips To Prevent A Car From Overheating.

Remembering a few quick tips as you drive can help to alleviate permanent engine damage down the road.

  • Check your vehicle’s coolant levels on a consistent basis.
  • Store an extra bottle of new antifreeze and a gallon of water in your trunk.
  • Monitor your car’s thermostat as you’re driving.
  • Do not overuse the car’s air conditioning on extremely hot days.
  • Help cool the engine by running the heat at the first sign of overheating.
  • Refer to the vehicle owner’s manual to stay up to date on coolant service flushes.

An overheating engine is a sign of a serious issue. Regular maintenance checks will help identify problems early on, before causing permanent damage to your vehicle.